A delay line is an apparatus for receiving an analog input signal and generating accordingly a plurality of output signals, wherein said output signals are substantially similar to the input signal but are delayed and uniformly displaced in time. For example, a particular delay line receives an analog input signal of 1 GHz and generates five output signals that are of the same frequency (1 GHz) but uniformly displaced in time with a spacing of 100 ps. A delay line usually employs a plurality of delay cells that are cascaded in sequence for generating a plurality of output signals, respectively. As long as said delay cells are substantially identical, the output signals are substantially similar but uniformly displaced in time. However, the delay cells are practically limited in bandwidth, and therefore the time spacing in the output analog signal is frequency dependent. A broad-band delay cell maintains substantially the same time spacing for signals ranging from DC to a high frequency. A broad-band delay line usually employs a plurality of transmission lines or distributed L-C networks. For an integrated circuit implementation, however, transmission lines and distributed L-C networks both demand large circuit areas. An active delay line employs transistors to achieve the function of delay. For an integrated circuit implementation, an active delay line is usually highly efficient in circuit area but the bandwidth is usually highly limited without consuming a high power to drive up the circuit speed. What is needed is a power efficient broad-band active delay line.